This invention relates generally to aircraft ventilation systems and, more specifically, ventilation systems for air crew and flight attendant rest areas.
Commercial aircraft around the world often undertake flights in excess of eight hours in length. Because of a need for adequate rest facilities for the flight crew and cabin crew members, rest areas are sometimes provided within the aircraft for use by the crew members while the aircraft is in flight or on the ground. Typically, the rest areas are relatively small, such as single person units remotely located in the vicinity of the aircraft""s cockpit.
Ventilation systems in the rest areas are typically tied directly into the aircraft""s main ventilation system. Obtaining and maintaining a habitable environment within the rest areas and complying with safety regulations has been a problem due to a number of factors, including a relatively large size of the main ventilation system of the aircraft, wide ranging atmospheric environmental conditions, the relatively small size of the rest areas, and the location of the rest areas in remote parts within the aircraft.
Cool air pulled from the aircraft""s main air conditioning pack is often excessively cold for relatively small rest areas. If the aircraft""s main ventilation system is continually running, the rest area is too cold to occupy until the rest area can be adequately heated. Conversely, if the ventilation system is shut down for any appreciable length of time, especially in warmer climates, the rest areas can become too hot to occupy. In either case, the rest areas and the items within the rest area represent a thermal mass that increases the time required to heat or cool the space to a habitable level. This additional uninhabitable period reduces the amount of time a crew member can rest, potentially preventing some crew members from receiving enough rest.
Another problem with pulling air directly from the main air conditioning pack is the adverse effect on ventilation system components. More specifically, under certain atmospheric conditions, such as those encountered on the ground or in flight below 25,000 feet, icing can occur in the ventilation system. Icing is particularly likely under warm, humid conditions in which moist air drawn from outside the aircraft is cooled and freezes within the ductwork. Icing can detrimentally affect operation of shut-off valves and other components downstream from the air conditioning packs, creating an undesirable or uncertifiable ventilation condition. Frozen valves are particularly troublesome when the valves operate a system to exhaust smoke from the cabin.
Therefore, there is an unmet need for a system for maintaining habitable conditions in aircraft crew rest areas and to prevent freezing of valves that operate critical exhaust systems.
The invention provides a reliable system for controlling crew rest air ventilation temperature such that the crew rest area climate is continually maintained in a habitable condition on the ground and at all flight altitudes.
The present invention provides a temperature control system for an aircraft ventilation system that couples with existing aircraft upstream ventilation system architecture and downstream ventilation system architecture. The temperature control system includes an air duct arranged to receive a volume of ventilation air from the upstream ventilation system architecture and transfer the volume of air to the downstream ventilation system architecture. A heater is used to heat the ventilation air, while a temperature sensor senses the temperature of the ventilation air. A controller maintains the actual ventilation air temperature such that formation of ice is minimized in the aircraft ventilation system.
In accordance with further aspects of the invention, the present invention provides a method of preventing icing conditions in an aircraft ventilation system. The method includes receiving ventilation air from an upstream ventilation system architecture of an aircraft ventilation system, passing the ventilation air through a heater at a first location and sensing an actual ventilation air temperature at a second location downstream from the first location. A controller controls the heater to maintain the actual air temperature. The continual sensing, comparing and controlling of the air ventilation temperature minimizes the formation of ice in the aircraft ventilation system.